diff --git a/asm/creole.py b/asm/creole.py
index 1ed25e8..1d105a1 100644
--- a/asm/creole.py
+++ b/asm/creole.py
@@ -50,13 +50,23 @@ class TypecheckException(Exception):
 		self.opcode = opcode
 	def __str__(self):
 		return f'opcode {self.opcode} has invalid value {self.sarg} (expected {self.argtype} in position {self.i}'
-class Instruction:
-	def __init__(self, opcode, argtypes):
+class Instruction(Enum):
+	NOP = 0
+	PUSH = 1, ArgType.VAL
+	POP = 2, ArgType.REG
+	ADD = 3, ArgType.VAL, ArgType.VAL, ArgType.VAL
+	MUL = 4, ArgType.VAL, ArgType.VAL, ArgType.VAL
+	DIV = 5, ArgType.VAL, ArgType.VAL, ArgType.VAL
+	JL = 6, ArgType.LAB, ArgType.VAL, ArgType.VAL
+	CLB = 7, ArgType.LAB
+	SYS = 8, ArgType.VAL
+
+	def __init__(self, opcode, *args):
 		if opcode > 0x7F or opcode < 0:
 			raise OpcodeException(opcode)
 
 		self.opcode = opcode
-		self.argtypes = argtypes
+		self.argtypes = args
 	def typecheck(self, sargs):
 		rargs = []
 		if len(sargs) != len(self.argtypes):
@@ -71,18 +81,6 @@ class Instruction:
 			rargs.append(t)
 		return rargs
 
-instructions = {
-"nop" : Instruction(0, []),
-"push" : Instruction(1, [ArgType.VAL]),
-"pop" : Instruction(2, [ArgType.REG]),
-"add" : Instruction(3, [ArgType.VAL, ArgType.VAL, ArgType.VAL]),
-"mul" : Instruction(4, [ArgType.VAL, ArgType.VAL, ArgType.VAL]),
-"div" : Instruction(5, [ArgType.VAL, ArgType.VAL, ArgType.VAL]),
-"jl" : Instruction(6, [ArgType.LAB, ArgType.VAL, ArgType.VAL]),
-"clb" : Instruction(7, [ArgType.LAB]),
-"sys" : Instruction(8, [ArgType.VAL])
-}
-
 encoding_types = {
 #           start      mask   A  B
 	2: (0x7F,       0xC0, 7),
@@ -165,12 +163,14 @@ class Program:
 	def parse_asm_line(self, line):
 		line = line.split()
 		line[0] = line[0].casefold()
-		if line[0] not in instructions:
+		try:
+			# TODO: is there no better way to do this in Python?
+			ins = getattr(Instruction, line[0].upper())
+		except Exception as e:
 			raise InstructionNotFoundException(line[0])
-		else:
-			ins = instructions[line[0]]
-			args_w_type = ins.typecheck(line[1:])
-			self.asm_push_line(ins.opcode, args_w_type)
+
+		args_w_type = ins.typecheck(line[1:])
+		self.asm_push_line(ins.opcode, args_w_type)
 
 	def __call__(self):
 		b = bytes()
diff --git a/asm/test.py b/asm/test.py
index 06a878f..640f3bf 100644
--- a/asm/test.py
+++ b/asm/test.py
@@ -9,7 +9,7 @@ class PushTest(unittest.TestCase):
 		b = p()
 		self.assertEqual(b, b'\x01\xC2\x85\x00')
 		ins = ffi.parse_line(b)
-		self.assertEqual(ins[0], instructions["push"].opcode)
+		self.assertEqual(ins[0], Instruction.PUSH.opcode)
 		self.assertEqual(ins[1][0], (1,5))
 
 	def test_parse_push_imm(self):
@@ -18,7 +18,7 @@ class PushTest(unittest.TestCase):
 		b = p()
 		self.assertEqual(b, b'\x01\xC0\x85\x00')
 		ins = ffi.parse_line(b)
-		self.assertEqual(ins[0], instructions["push"].opcode)
+		self.assertEqual(ins[0], Instruction.PUSH.opcode)
 		self.assertEqual(ins[1][0], (0,5))
 
 	def test_parse_push_catch_typecheck_push_lab(self):
@@ -55,7 +55,7 @@ class PushTest(unittest.TestCase):
 	def test_compile_push(self):
 		p = Program()
 		p.parse_asm_line("PUSH r0")
-		p.parse_asm_line("PUSH r6")
+		p.parse_asm_line("PUSH 6")
 		b = p()
 
 		ex = ffi.ExecutionEnvironment()
@@ -71,7 +71,7 @@ class PushTest(unittest.TestCase):
 		self.assertEqual(ex.cenv.prg[0].w[2], 0)
 
 		self.assertEqual(ex.cenv.prg[1].opcode, 1)
-		self.assertEqual(ex.cenv.prg[1].w_flags[0], 1)
+		self.assertEqual(ex.cenv.prg[1].w_flags[0], 0)
 		self.assertEqual(ex.cenv.prg[1].w_flags[1], 0)
 		self.assertEqual(ex.cenv.prg[1].w_flags[2], 0)
 		self.assertEqual(ex.cenv.prg[1].w[0], 6)
@@ -109,7 +109,7 @@ class ProgramTest(unittest.TestCase):
 		p = Program()
 		p.parse_asm_line("add r1 23 3648")
 		ins = ffi.parse_line(p())
-		self.assertEqual(ins[0], instructions["add"].opcode)
+		self.assertEqual(ins[0], Instruction.ADD.opcode)
 		self.assertEqual(ins[1][0], (1,1))
 		self.assertEqual(ins[1][1], (0,23))
 		self.assertEqual(ins[1][2], (0,3648))